You can make apps with game engines, great thing with them is they have a lot of tools to make things simple.
Torque3d, UDK, Unity 3d, I use Unity and it's awesome. I write my code in C#, and since I have iOS and android licenses, I can in a couple clicks output a native xcode app or native apk for android, from the same code. (have to have a mac to output iOS though, but can output apk on a mac) In a single click you can switch from OpenGL 1 and 2, or target a specific OS. I interface with mysql and php and have access to extra stuff like mac address, GPS coordinates, etc super easy.